Wafer level packaging allows packaging an integrated circuit while it remains in the wafer. It is a chip-scale package technology. WLP can integrate wafer fabrication, packaging, test, and burn-in at the wafer level in order to streamline a device's manufacture. It consists of extending the wafer fabrication processes to include device interconnection. WLP attaches the top and bottom outer layers of packaging, and the solder bumps, to integrated circuits while still in the wafer, and then dicing the wafer.
Different types of WLP exists, such as fan-in WLP and fan-out WLP. Fan-in WLP uses layout package connections within the chip area, and when the scale and count of on-chip bond pads does not match with standard packaging scales, a RDL of metal interconnect can be used to fan-in to ball-grid or pillar-grid arrays (BGA/PGA) within the chip-area. However, when the needed number of connections cannot be made within the chip area, mold compound materials can be used to provide physical area adjacent to an original chip such that package connections can be arranged on a fan-out area when seen from above.
To reduce manufacturing costs further, a fan-in WLP process for manufacturing an 8″ Si wafers may use a 12″ fan-out WLP process. This can result in a significant cost saving (up to 30%). However, to build a traditionally fan-out WLP requires adding a thick mold compound to the sidewalls. It's extremely difficult to reduce sidewall width and minimize form factor to match fan-in wafer level package.
One of these difficulties in fan-in WLP products can be sidewall chipping and cracking, which can cause yield loss and lead to surface mount technology failures and reliability failures. Sidewall chipping and cracking can account for a high level of customer returns. Current semiconductor assembly and tests are unable to control chipping and cracking within ten percent of the die's width and length. Current automatic inspections can provide quality assurance measures, but the capital investment and reduced throughput can be costly. Furthermore, the cracking and chipping may not be eliminated using automatic inspections, but merely prevented from reaching the customer.
Accordingly, there is a need for systems, apparatus, and methods that improve upon conventional approaches including the improved methods, system and apparatus provided hereby.